The embodiments described in this disclosure relate to messaging systems such as text messaging systems on cellular telephones or other communication devices or data processing systems.
The use of text messaging systems began many years ago. For example, wireless cellular telephone carriers, such as Verizon or AT&T, allowed text messages through the Short Message Service (SMS) for cell phones in the 1990s before smartphones were available. Typically, the amount of data transmitted has been limited by rules established by the carriers. Recently, as the use of smartphones (e.g. iPhones) and tablet computers (e.g. iPad) has increased, the text messaging systems have developed the ability to send images, such as photos or emojis. In addition, messaging systems such as iMessage from Apple Inc. of Cupertino, Calif. have allowed users to also send and receive text and images through “public” networks which include “public” WiFi access points and the Internet (in addition to using the wireless carrier's private cellular telephone networks), and messaging systems such as iMessage can seamlessly transition between the use of public and private networks depending on the availability of, for example, WiFi access points or the compatibility of the other user's device (which may not be compatible with iMessage).